1. Field of the Invention
The present invention relates to a photodetector for simultaneous recognition of multiple wavelengths, and a method therefor, by which when lights of various wavelengths are transmitted through a single filter, those transmitted lights can be recognized at the same time, and then be processed.
2. Description of the Conventional Art
To meet the continuously increased demands for exchanging the required information, the information processing speed in the light transmission fields has been continuously improved. To this end, there is currently provided a scheme of WDM(wavelength division multiplexing) under development in which the transmission amount per unit time is further increased through simultaneous transmission of various wavelengths. Thus, what is needed is to develop wavelength variable light source suitable for WDM method, multiple-wavelength light source, wavelength variable-type photodetector, photodetector for simultaneous detection, etc.
For the wavelength division multiplexing method, since the lights including various wavelengths are transmitted through a single fiber, it is required to individually extract each information embedded in the transmitted lights. A conventional method for detecting the multiple lights employs gratings, each being provided with each detector, so as to individually isolate each wavelength, but requires the sophisticated works and loss of cost in manufacturing the gratings, furthermore resulting in the complicated detector configuration.
Further, there may be employed another method in which the fibers inscribed with grating therein are used, as much as the number of wavelengths, so as to extract each light corresponding to each wavelength, but results in an inconvenience and loss, similarly.
Still further, a semiconductor-based filter may be used for applications as mentioned above. This approach using the filter equally divides the transmitted lights, and then selects only one wavelength as desired. However, this approach has a problem in that a considerable loss of the incident light at a boundary between the light fiber and the light element occurs, and the light receiving parts are very complicated.
As mentioned above, through any one among the conventional methods may be extracted one wavelength of multiple wavelengths and then processed, but in which those methods have disadvantages of a weaken intensity of the light which is transmitted, a complicated detector, and difficulty in manufacturing the device.